<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="./main.css">
  <style>
    [class="p1 p2"] {
      color: red;
      font-size: 40px;
    }
  </style>
</head>

<body>
  <a class="p1 p2" href="./a.html">a.html</a>
  <!-- 层叠 -->
  <a class="p1" href="./b.html" title="this is b.html">b.html</a>
  <p class="p1">this is p1</p>
  <p class="p2">this is p2</p>
</body>

</html>